Overfishing a threat, Florida studies say
KEY LARGO, Fla. — Key Largo is home to one of the world’s most vibrant coral reef systems, but overfishing of important herbivorous or plant-eating fish could threaten the health of these wonders enjoyed by divers and snorkelers alike.
Deron Burkepile, 34, assistant professor of marine biology and oceanography at Florida International University, discovered this in 2004 during a ten-day research mission on board the world’s only underwater ocean research center, the Aquarius Undersea Laboratory.
Located in the Florida Keys National Marine Sanctuary, Aquarius sits approximately 60 feet deep at the base of Conch Reef, about four miles from Key Largo. The undersea lab is operated by the University of North Carolina Wilmington and is owned by the National Oceanic and Atmospheric Association (NOAA).
By living in the submarine-like pressurized habitat, divers’ bodies become saturated with the maximum partial pressure of gas possible for that depth, a technique called saturation diving. Once their body tissues are saturated, researchers can dive for up to nine hours a day and avoid the deadly decompression sickness known as “the bends” when they come to the surface.
After a long day of diving, these scientists – also called aquanauts – eat, sleep and use the Internet. They can remain in the underwater lab for days at a time, something unheard of up to now.
This is possible because of the Life Support Buoy that floats on the surface above the lab and is about 30 feet in diameter. The buoy is a platform connected to the sea lab that provides all the gases needed for breathing underwater.
But the underwater experience may not be comfortable for some. “The hardest part is being cold all the time and constantly losing body heat,” Burkepile said, referring to the heavy air conditioning used in the lab to keep the correct air balance.
Joseph Pawlik, 51, professor of marine science at University of North Carolina, Wilmington, has conducted four missions since 1995 but has never been an aquanaut himself. “I get cold too easily,” Pawlik said. “But I never have trouble finding interested students to send down. The hardest part is denying students the opportunity to go.”
Divers spending prolonged time underwater can conduct extensive research that would be impossible if they needed to return to the surface frequently. The lab also saves time and money, since researchers are much closer to their work.
On Pawlik’s most recent mission, he sent students to monitor Caribbean barrel sponges. Information gathered by the aquanauts could be important in monitoring the future effects of the BP oil gusher in the Gulf of Mexico.
Scientists who want to use the Aquarius for research submit grant proposals to the National Oceanic and Atmospheric Administration. If the proposals are deemed useful, scientists are invited to conduct their work in the lab. Research done at Aquarius can help benefit marine habitats not only in South Florida, but also around the world.
The Aquarius was built in 1986 and was first used in the Virgin Islands. Thirteen missions later, it was moved to Wilmington to be refurbished after damage from Hurricane Hugo. In 1993, it was moved to its current location and has since been the base for more than 90 successful missions, including Burkepile’s.
The director of Aquarius, Thomas Potts, 46, said that since the lab has been in Key Largo, “Scientists have acquired a long-term dataset that is essential to comprehensively and intimately studying and documenting changes in a coral reef ecosystem that could not be attained by disparate research projects alone.”
Burkepile’s mission is proof of that. His project was designed to reveal the need for diversity of herbivorous fish in coral reef systems. He and his group placed small cages along Key Largo’s reef system to study how different fish eat different types of seaweed. “We got to eat, sleep, and dive,” Burkpile said. “It was awesome.”
After diving nine hours a day for ten days, Burkepile and his scientific group found that certain seaweed species aren’t eaten enough and their overgrowth could potentially harm the corals. He and his team also concluded that overfishing of certain herbivorous fish was affecting the seaweed balance and, therefore, the health of the coral systems.
Burkepile’s missions, along with others done at the laboratory, have helped produce more than 300 peer-reviewed scientific publications. But scientific research isn’t the only use for Aquarius.
Potts said the sea lab is also used for developing undersea technology and for ocean education and outreach. In addition, it serves as a national training facility for scientific divers.
Unlike Jules Underwater Hotel in Key Largo, which accepts guests with no scuba training, not just anyone can stay at Aquarius. Divers must go through five days of SCUBA training to qualify for working at the lab. “We had to go through intense training,” Burkepile said. “Our instructors would mess with us, pull off our masks, and imitate actual emergency situations.”
Leaving Aquarius in the same underwater location over time has contributed to its success. “I think the biggest benefit of the Aquarius is that it has been in place for 20 years in one location,” Potts said. “We can document long-term changes and have long-term data, which is very rare.”
Pawlik agrees. “Key Largo is an excellent location with a great reef system,” he said. “There is a lot of topography and internal waves. The longer the laboratory is there, the more valuable information we can get.”